Craig Patterson, Jonathan Burkhardt USEPA, ORD, Cincinnati, Ohio

Stephen Dyment, USEPA OSP, Denver, Colorado

Steven Merritt USEPA Region 8, Denver, Colorado

Larry Zintek, Danielle Kleinmaier USEPA Region 5, Chicago, Illinois

E. Radha Krishnan, Donald Schupp APTIM, Cincinnati, Ohio

1

Effectiveness of Point-of-Use/Point-of-Entry Systems to Remove

Widefield Aquifer Per- and Poly- fluoroalkyl Substances from Water

Source: Denver Post

Region 8 CLUIN Webinar November 26, 2018

Extent of PFAS Contamination

2

Source: Esri, HERE,

Garmin, NGA, USGS, NPS

Source: KRDO.com

PFAS Contaminants

3

Unregulated Contaminant Monitoring

Rule 3 (UCMR3) PFAS detected in the

Widefield Aquifer:

Perfluorooctanoic Acid (PFOA)

Perfluorooctane Sulfonate (PFOS)

Perfluoroheptanoic Acid (PFHpA)

Perfluorobutane Sulfonate (PFBS)

Perfluorononanoic Acid (PFNA)

Perfluorohexane Sulfonic Acid

(PFHxS).

Aqueous Film Forming Foam (AFFF) was used to fight fires at

Peterson Air Force Base. As of August of 2016, a new product

Phos-Chek 3 with shorter chain molecules is now being used.

U.S. Air National Guard photo by Airman 1st Class Amber Powell

Potential health impacts: Cancer, liver, thyroid, pancreatic, kidney and fertility problems

Response Actions and Alternative Water Sources

4

Source: Colorado Springs Gazette

Surface water is being blended from Pueblo Reservoir to

meet the PFOA/PFOS health advisory and PCE maximum

contaminant levels (MCLs).

Bottled water stations and water coolers provide alternative

drinking water sources to residents living in the Widefield

Aquifer region.

Project Goal

5

To assess the removal effectiveness of target Per- and Poly- fluoroalkyl

Substances (PFAS) using commercially available Point-of-Use (POU)

and Point-of-Entry (POE) Reverse Osmosis (RO) treatment units and

Granular Activated Carbon (GAC) adsorption systems for homes with

private wells in Colorado’s Widefield Aquifer. To meet this goal, the

project purchased commercially available household water systems and

conducted treatability studies on representative test waters.

Point-of-Use (POU)

Kitchen sink, end-of-faucet,

and pour-thru devices

Point-of-Entry (POE)

Whole House; typically installed in a

hot water tank room or a heated garage

R8 RARE Project Objectives

6

The project also documented:

Ease of use during installation,

startup, continuous and intermittent

operation based on manufacturer

instructions.

Operation and maintenance

schedules for replacement of RO

units and GAC media based on

manufacturer instructions and the

representative test water quality.

Source: H2O Distributors

NSF Standard P473

7

NSF Standard P473 for Drinking Water Treatment Units - PFOA and PFOS is a test

method for point-of-use carbon-based and reverse osmosis treatment systems to

determine their ability to reduce perfluorooctanoic acid (PFOA) and perfluorooctane

sulfonate (PFOS) to below the EPA Healthy Advisory Level of 70 parts per trillion.

Water treatment systems, including water filters, must verify that:

Contaminant reduction claims for PFOA and PFOS shown on the label are true

The system does not add anything harmful to the water

The system is structurally sound

The product labeling, advertising and literature are not misleading

NSF Std P473

Individual influent

sample point limits

Average influent

challenge

Maximum

effluent

concentration

μg/L μg/L μg/L

PFOS and PFOA 1.5 ± 30%

1.5 ± 10%, added as

1.0 μg/L PFOS and 0.5

μg/L PFOA

0.07

Widefield Aquifer PFAS

8

Maximum Widefield Aquifer PFAS Concentrations (ng/L)

Sample

Dates PFBS PFHxS PFNA PFHpA PFOA PFOS

PFOS+

PFOA

2013-2016 260 970 150 200 200 1600 1800

Average Widefield Aquifer PFAS Concentrations (ng/L)

Sample

Dates PFBS PFHxS PFNA PFHpA PFOA PFOS

PFOS+

PFOA

2013-2016 71 203 16 24 43 137 180

Source: Colorado Department of Public Health and Environment website.

Test Water Target PFAS Composition

9

CAS

Number PFAS Compounds

Carbon

Chain

Length

Target

Concentration

375-95-1 Perfluorononanoic Acid (PFNA) C9 200 ng/L

335-67-1 Perfluorooctanoic Acid (PFOA) C8 *800 ng/L

1763-23-1 Perfluorooctane Sulfonate (PFOS) C8 1,600 ng/L

375-85-9 Perfluoroheptanoic Acid (PFHpA) C7 200 ng/L

3871-99-6 Perfluorohexane Sulfonate (PFHxS) C6 1,000 ng/L

375-73-5 Perfluorobutane Sulfonate (PFBS) C4 300 ng/L

*To align with the NSF P473 specified 2:1 PFOS:PFOA ratio, the

PFOA feed concentration was increased from 200 ng/L to 800 ng/L.

Widefield Aquifer WQ (1992-2016)

10

BDL= BELOW DETECTABLE LIMIT

MCL = MAXIMUM CONTAMINANT LEVEL

MSL = MAXIMUM SUGGESTED LEVEL

NLE = NO LIMITS ESTABLISHED

PARAMETER MCL MAX VALUE UNITS PARAMETER MCL MAX VALUE UNITS

2,4,-D 0.07 0.10 mg/L MAGNESIUM MSL = 125 mg/L 18 mg/L

ALKALINITY TOTAL NLE 220 mg/L as CaCO3 MANGANESE MSL = 0.05 mg/L BDL mg/L

ANTIMONY 0.006 0.00 mg/L MERCURY 0.002 0.000 mg/L

ARSENIC 0.01 0.06 mg/L MOLYBDENUM NLE BDL mg/L

BARIUM 2 0.90 mg/L N_NITRATE / NITRITE 10.0 mg/L 7 mg/L

BERYLLIUM 0.004 0.000 mg/L NICKEL NLE 0.01 mg/L

CADMIUM 0.005 0.000 mg/L NITRATE 10 9.8 mg/L

CALCIUM NLE 170 mg/L as CaCO3 NITRITE 1 BDL mg/L

CHLORIDE MSL = 250 MG/L 23 mg/L PCE (TETRACHLOROETHYLENE) 0.005 0.033 mg/L

CHROMIUM (TOTAL) 0.1 0.08 mg/L PENTACHLOROPHENOL 0.001 0.040 mg/L

COLOR (TRUE, APPARENT) MSL=15 Color Units <5.0 pt/Co Units pH 6.5-8.5 6.25 to 8.17 s.u.

CONDUCTIVITY NLE 470 uhm/Cm PHOSPHATE, PHOSPHORUS NLE 0.07 mg p/H

COPPER Action Level=1.3 mg/L 25 mg/L SELENIUM 0.05 0.01 mg/L

CYANIDE 0.2 0.000 mg/L SODIUM NLE 57 mg/L

DI(2-

ETHYLHEXYL)PHTHALATE 0.006 0.0025 mg/L TOTAL DISSOLVED SOLIDS (TDS) MSL = 500 mg/L 490 mg/L

EPICHLOROHYDRIN NLE 3.1 mg/L SPECIFIC CONDUCTIVITY NLE 470 umhos

FLUORIDE 4.0 2.6 mg/L SULFATE MSL=250 mg/L 116.00 mg/L

GROSS ALPHA 15 14 pCi/L TEMPERATURE NSF P473 20 ± 3 °C 13 to 15 deg. C

HARDNESS CALCIUM NLE 230 mg/L THALLIUM 0.002 0.000 mg/L

HARDNESS TOTAL NLE 290 mg/L as CaCO3 TOTAL ORGANIC CARBON (TOC) NLE 1.19 mg/L

IRON MSL = 0.3 mg/L BDL mg/L TOTAL SOLIDS NLE 433 mg/L

LANGLIER INDEX NLE -0.34 to -0.5 TURBIDITY 1 NTU <0 NTU

LEAD Action Level=0.015 0.012 mg/L ZINC MSL = 5.0 mg/L BDL mg/L

Test Water Target Water Quality Characteristics

11

General Chemistry Water Parameters

Temperature (°C) RO: 25 ± 1°C, GAC: 20 ± 2.5°C

pH (pH Units) 8.2 ± 0.5

Turbidity (NTU) <1 NTU

Free chlorine (mg/L) <0.2 mg/L

TOC (mg/L) RO: not specified (not adjusted)

GAC: >1 mg/L (added as dehydrated NOM)

TDS (mg/L) RO and GAC: 500 mg/L (added as NaCl)

Hardness (mg/L)

RO: 300 mg/L CaCO3 (added as potassium chloride

[KCl], magnesium sulfate [MgSO4], sodium

bicarbonate [NaHCO3] and calcium sulfate

[CaSO4·2H2O]), GAC: not specified.

Sample Collection, Handling and Preservation

12

Analyte Lab Container Preservation Holding Time

Per-and poly-fluoroalkyl

substances (PFAS) R5

15 mL Polypropylene

Container Cool <6°C 28 days

Temperature blank R5 One 40 mL Vial Cool <6°C

Measure

temperature upon

receipt

Total Organic Carbon

(TOC) T&E 100 mL Amber Glass

Cool <6°C, No

headspace H3PO4,

pH<2;

28 days

Total Dissolved Solids

(TDS) T&E 1 L HDPE Amber Cool <6°C 7 days

Turbidity T&E 100 mL HDPE or glass jar

or beaker Cool <6°C 48 hours

Hardness T&E 250 mL HDPE or glass jar pH <2, HNO3 6 months

Free Chlorine T&E 40-50 mL / Glass beaker None Analyze

Immediately

pH T&E 40-50 mL / Glass beaker None Analyze

Immediately

Temperature T&E 40-50 mL / Glass beaker None Analyze

Immediately

PFAS in Feed Water

13

GAC PFAS Target Stability Test GAC Test 1 GAC Test 2

PFOA (ng/L) 800 870-1150 926-1030 859-1070

PFOS (ng/L) 1600 139-288 1670-2740 1500-5210

PFHpA (ng/L) 200 240-296 277-332 267-287

PFBS (ng/L) 300 Non-Detect 360-405 347-379

PFHxS (ng/L) 1000 974-1180 999-1140 1020-1120

PFNA (ng/L) 200 208-304 245-310 231-448

RO PFAS Target Stability Test RO Test 1 RO Test 2 RO Test 3

PFOA (ng/L) 800 899-967 878-1080 799-2580 800-1030

PFOS (ng/L) 1600 130-163 1370-2680 1100-6770 1290-2920

PFHpA (ng/L) 200 233-277 330-384 315-470 240-271

PFBS (ng/L) 300 Non-Detect 316-380 361-382 333-362

PFHxS (ng/L) 1000 889-1070 964-1150 844-1930 927-1130

PFNA (ng/L) 200 207-242 219-381 192-967 192-199 5000 Gallon

Mix Tank

55 Gallon

Drum

WQ Results Summary

14

RO Test WQ

Parameters Target Stability Test RO Test 1 RO Test 2 RO Test 3

pH (s.u) 7.7-8.7 8.54-8.64 8.44-8.61 8.34-8.58 8.48-8.61

Temperature (°C) 24-26°C 24.9-29.1°C 22.0-23.1°C 21.8-23.1°C 22.0-24.4°C

TDS (mg/L) 500 mg/L 523-549 mg/L 514-576 mg/L 507-540 mg/L 446-456 mg/L

HARDNESS (mg/L) 300 mg/L 263-296 mg/L 285-323 mg/L 277-300 mg/L 240-298 mg/L

GAC Test WQ

Parameters Target Stability Test GAC Test 1 GAC Test 2

pH (s.u) 7.7-8.7 8.56-8.63 8.58-8.61 8.61-8.68

Temperature (°C) 17.5-22.5°C 20.9-26.5°C 20.7-22.3°C 19.6-20.3°C

FAC (mg/L) < 0.2 mg/L 0.01 mg/L 0.02 mg/L 0.01 mg/L

TDS (mg/L) 500 mg/L 528-563 mg/L 466-466 mg/L 471-471 mg/L

TOC (mg/L) > 1.0 mg/L 1.41-1.54 mg/L 2.35-2.52 mg/L 2.37-2.55 mg/L

Reverse Osmosis Systems

15

POU/POE treatment tests on three

RO systems (500-1000 gal/day):

iSpring RCS5T (0.35 gpm)

Hydrologic Evolution (0.7 gpm)

Flexeon LP-700 (0.5 gpm)

iSpring Hydrologic Sample Collection Flexeon

Summary of RO System Specifications

16 A Pressure and efficiency depend on the temperature and pressure of the feed water.

RO system iSpring RCS5T HydroLogic Evolution RO1000 Flexeon LP-700

Rated CapacityA 500 GPD (0.35 gpm) 1,000 GPD (0.7 gpm) 700 GPD (0.5 gpm)

Filters Included Sediment filter Carbon pre-filter Sediment filter

Carbon pre-filter 2 RO membranes Carbon pre-filter

CTO filter 2 RO membranes

RO membrane Carbon post-filter

Carbon post-filter

System RecoveryA 50% 50%, using 1:1 fitting 38%

Booster Pump Yes No No

Connections 3/8” Inlet ½” Inlet 3/8” Inlet and Outlet

¼” Outlet 3/8” Outlet (tubing not included)

(tubing included) (tubing included)

Self-Supporting Yes Yes No

Size (L x W x H) 8.5” x 15” x 18.5” 20.5” x 11” x 10” 18” x 10.5” x 32”

Weight 31 lbs 16 lbs 38 lbs

RO System Replacement Filters and Membranes

17

RO system iSpring RCS5T HydroLogic Evolution

RO1000 Flexeon LP-700

Sediment filter #FP15 (3-6 months) Not Part of System #200627 (12 months)

Carbon pre-filter #FG15 (6 months) #22043 (2,000 gallons of

purified water) #200658 (12 months)

Carbon block

filter #FC15 (6 months) Not Part of System Not Part of System

RO membranes #MS5 (24 months) #220445 (6 – 24 months) #208802 (24 months)

(requires 2) (requires 2)

Carbon post-

filter #FT15 (12 months) Not Part of System #200658 (12 months)

Reverse Osmosis Test Unit

18

Rotameter

with Valve

(1-3 L/min)

Heat Chiller

5000 Exchanger

Gallon

Tank

RO

Test

Unit

Clean

Recirculation (Sample)

Pump Reject to Drain

Sample Port to Drain

Sample Ports – Influent from 5000 gallon tank line and Effluent from RO permeate line.

RO System Sampling Plan

19

* No samples collected

Day #

Day of

Week

Time of

Day

Sample

Hour

Time of

Day

Sample

Hour

Time of

Day

Sample

Hour

Day 1 Tues AM Startup* Noon 4 hr PM 8 hr

Day 2 Wed AM 24 hr Noon 30 hr PM 36 hr

Day 3 Thurs AM 48 hr Noon 54 hr PM 60 hr

Day 4 Fri AM 72 hr Noon 78 hr PM 84 hr

Day 5 Sat 2 Day Stagnation Period*

Day 6 Sun

Day 7 Mon AM 144 hr PM 148 hr PM Shutdown*

Day 8 Tues Ship

20

All effluent PFAS results were non-detect

PFAS Removal vs. Time iSpring RO#1

21

PFAS Removal vs. Time Hydrologic RO#2

6 of 42 PFAS results were greater than non-detect

22

RO Test 2 PFAS Results > Non-Detect

PFC Time

(hr)

Influent

Conc.

(ng/L)

Effluent

Conc.

(ng/L)

Removal

Efficiency

(%)

PFOS 8 1100 22 98.0

PFOS* 144 1360 77 94.3

PFOA* 144 799 21 97.3

PFHxS 144 844 11 98.7

PFNA 144 210 49 76.7

PFOS 148 1330 20 98.5

* Exceeded the 70 ng/L PFOS+PFOA EPA Health Advisory Level

23

All effluent PFAS results were non-detect

PFAS Removal vs. Time Flexeon RO#3

24

1/8" or 1/4" SS Tubing To sink

(depending on

pump fittings)

Carbon

column

0 - 200 psi 3/8" x 6"

55-gallon SS tubing

Stainless Steel 0.28125" ID

Drum

Pressure To sink

Gear Relief

Pump Valve (200 psi)

M

PI

GAC Test Unit

Rapid Small Scale Column Test (RSSCT)

Sample Ports – Influent from 55 gallon drum, Effluent from SS tubing every 30 min for 8 hrs.

25

GAC Characteristics and RSSCT Design Parameters

Parameter Test 1 Test 2

GAC Evoqua 1230CX Calgon Filtrasorb 600 AR+

Source Coconut Bituminous Coal

Density 0.45 g/cm3 0.62 g/cm3

Porosity 0.47 0.39

Mesh Size 12 x 30 12 x 40

EBCTLC 10 min 10 min

dp,LC 1.150 mm 1.063 mm

dp,SC 0.0825 mm 0.0825 mm

Scaling Factor 194.3 165.9

QSC 10 mL/min 10 mL/min

VSC 0.515 mL 0.603 mL

MSC 0.2294 g 0.3742 g

GAC RSSCT Media

26

Commercially available

GAC media tested:

Evoqua 12x30 Mesh

RSSCT 170x200 Mesh

Calgon 12x40 Mesh

RSSCT 170x200 Mesh

Grinding and Sieving

GAC to meet RSSCT

Mesh Screen Sizes

GAC

27

Maximum PFAS Concentrations vs. Time Evoqua GAC#1

28

Maximum PFAS Concentrations vs. Time Calgon GAC#2

Modeling of GAC Results

29

To investigate the impact of PFAS influent concentrations on GAC

(bed volumes to breakthrough at 70 ng/L PFOS+PFOA), the

AdDesignS™ model (Michigan Tech. Univ., v1.0, 1999) was used to

predict GAC lifetime based on average PFOA (43 ng/L) and PFOS

(137 ng/L) concentrations based on historic records (2013–2016)

found in Widefield Aquifer region water samples.

The PFOS+PFOA concentration in the influent was approximately

3,000 ng/L for the worst-case scenario and 180 ng/L for the average

day (a 16-17x reduction). For the maximum day, the model

predicted an exceedance of the PFOS+PFOA Health Advisory Level

(HAL) of 70 ng/L after approximately 3,400 bed volumes for Evoqua

GAC#1 and approximately 2,700 bed volumes for Calgon GAC#2,

which is consistent with the experimental values.

30

Average PFAS Conc. vs. Bed Volumes Evoqua GAC#1

Model results of PFOS and PFOA

effluent concentrations

Predicted Max. PFOS+PFOA >

HAL of 70 ng/L after 3,400 BVs

(24 days of operation)

Predicted Avg. PFOS+PFOA >

HAL of 70 ng/L after 115,000

BVs (2.2 years of operation)

31

Average PFAS Conc. vs. Bed Volumes Calgon GAC#2

Model results of PFOS and PFOA

effluent concentrations

Predicted Max. PFOS+PFOA >

HAL of 70 ng/L after 2,700 BVs

(19 days of operation)

Predicted Avg. PFOS+PFOA >

HAL of 70 ng/L after 79,000

BVs (1.5 years of operation)

25”

28”

$360

64#

RO Modification for Point-of-Entry Use

32

6’2”

31”

$280 67#

225

Gallons

$2000 before

installation,

Weight: 150 lbs

Requires at least

a 4’x4’ Room.

May require a re-

mineralization

cartridge.

Requires Electricity for Well, RO Booster and Water Storage Tank Pumps

RO = $500

RO Booster

Pump = $880

Typical Household GAC System

33

Typical 4-5 GPM Non-Backwashing Whole House Carbon Filter with

5 and 1 micron pleated sediment cartridges (Source: H2O Distributors)

Large Whole House Carbon Tanks Required for PFAS Removal (10 min EBCT each)

34

Two Large Whole House

Backwashing Carbon Water Filter

($3990) 65”(H) x 16”(D) tank

with 240 lbs (8 cu ft) of GAC

(Source: H2O Distributors)

One 4-5 GPM Non-Backwashing

Whole House Carbon Water Filter

($539) 35”(H) x 9”(D) tank with

30 lbs (1 cu ft) of GAC

(Source: H2O Distributors)

62#

165# 165#

GAC Modification for PFAS Removal

35

5’5”

16” 16”

$1995

165#

30

Gallons $4000 before

installation,

Weight: 330 lbs

$1995

165#

30

Gallons

Well Water Flow

must be restricted

to 5 gpm

25”

28”

$360

64#

Small GAC System for PFAS Removal

36

6’2”

31”

$280 67#

225

Gallons

$1200 before

installation,

Weight: 200 lbs

35” $540

62#

9”

Requires at least

a 4’x4’ Room

*Requires more frequent GAC replacement

Well Water

Flow must

be restricted

to 0.5 gpm*

Comparison of Household GAC and RO System Alternatives

37

Large GAC Adsorption

System

Small GAC Adsorption

System RO System

High capital and high

maintenance costs

Moderate capital and

high maintenance costs

Moderate capital and

maintenance costs

Large footprint and

heavy components

Large footprint and

awkward components

Large footprint and

awkward components

Higher flow rate

(4-5 gpm). No water

storage tank required

Lower flow rate

(0.5 gpm) requires water

storage tank

Lower flow rate

(0.3-0.7 gpm) requires

water storage tank

Requires backwash

wastewater lines and

periodic carbon

replacement

Fewer connections, but

requires more frequent

carbon replacement

Requires high system

pressure, reject

wastewater lines and

periodic membrane

replacement

38

GAC Adsorption System RO System

Issues with logistical, cost and safety

of carbon replacement

Issues with sanitizing components

and replacing cartridges & tubing

Cold water temperature less affected

in flow through carbon tanks

Residents may complain about

“cold” water at room temperature

in water storage tank

May not be effective on short-chain

PFAS

Treats both long- and short- chain

PFAS

System could experience contaminant

breakthrough if the carbon change-out

schedule is not followed.

Less likely to have contaminant

breakthrough even if scheduled

maintenance is not performed.

Corrosion control in household

plumbing may be an issue for

point-of-entry water treatment.

Comparison of Household GAC and RO Systems

Conclusions

39

The three RO systems tested successfully removed PFAS from

the influent water to below analytical detection for a majority

of the sampling events. However, long-term performance of

the membrane systems was not tested.

RSSCT data estimated that the coal-based Calgon F-600 GAC

would have a lifetime of 20 days compared to the coconut-

based Evoqua GAC lifetime of 33 days based on maximum

PFAS concentrations tested before exceeding the EPA’s HAL

of 70 ng/L for PFOS and PFOA.

Modeling the results for lower concentrations (average daily

concentrations) gave bed lives of 1.5 years for the Calgon F-

600 GAC and 2.2 years for the Evoqua Coconut carbon.

However, additional pilot-tests should be performed to ensure

the use of the best performing GAC for each application.

Conclusions

40

If properly designed based on the source water

characteristics, POU/POE water systems can provide

relatively inexpensive treatment barriers for PFAS

removal in the home.

Analysis of PFAS samples is costly for homeowners and

can be a major hurdle in effective removal of PFAS from

household water supplies.

Proper operation and maintenance and conservative

replacement of POU/POE components and media may be

one way to circumvent the high cost of monitoring treated

household drinking water.

The U.S. Environmental Protection Agency, through its Office of

Research and Development, funded and managed, or partially

funded or collaborated in, the research describe herein. It has

been subjected to the Agency’s peer and administrative review

and has been approved for external publication. Any opinions

expressed in this paper are those of the author (s) and do not

necessarily reflect the views of the Agency, therefore, no official

endorsement should be inferred. Any mention of trade names or

commercial products does not constitute endorsement or

recommendation for use.

Disclaimer

41

Office of Research and Development National Risk Management Research Laboratory – Water Supply and Water Resources Division

Photo image area measures 2” H x 6.93” W and can be masked by a

collage strip of one, two or three images.

The photo image area is located 3.19” from left and 3.81” from top of page.

Each image used in collage should be reduced or cropped to a maximum of

2” high, stroked with a 1.5 pt white frame and positioned edge-to-edge with

accompanying images.

Questions? Patterson.Craig@epa.gov